Electrical terminal for flat flexible cables
A cable assembly includes a flat flexible cable having a plurality of conductors embedded within an insulation material. A portion of each of the conductors is exposed via openings selectively formed in the insulation material, allowing for a crimping portion of an electrically conductive terminal to engage with the conductor within the opening. The crimping portion of the terminal includes a base defining at least one protrusion extending therefrom, and first and second sidewalls extending from the base. The base and sidewalls define an opening configured to receive the conductor therein, wherein the sidewalls are foldable into the opening for crimping the conductor within the opening and generally between the protrusion of the base and a portion of the sidewalls.
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The present disclosure relates to electrical terminals, and more particularly, to electrical terminals suitable for crimping to conductors of a flat flexible cable.
BACKGROUNDAs understood by those skilled in the art, flat flexible cables (FFCs) or flat flexible circuits are electrical components consisting of at least one conductor (e.g., a metallic foil conductor) embedded within a thin, flexible strip of insulation. Flat flexible cables are gaining popularity across many industries due to advantages offered over their traditional “round wire” counter parts. Specifically, in addition to having a lower profile and lighter weight, FFCs enable the implementation of large circuit pathways with significantly greater ease compared to a round wire-based architectures. As a result, FFCs are being considered for many complex and/or high-volume applications, including wiring harnesses, such as those used in automotive manufacturing.
The implementation or integration of FFCs into existing wiring environments is not without significant challenges. In an automotive application, by way of example only, an FFC-based wiring harness would be required to mate with perhaps hundreds of existing components, including sub-harnesses and various electronic devices (e.g., lights, sensors, etc.), each having established, and in some cases standardized, connector or interface types. Accordingly, a critical obstacle preventing the implementation of FFCs into these applications includes the need to develop quick, robust, and low resistance termination techniques which enable an FFC to be connectorized for mating with these existing connections.
A typical FFC may be realized by applying insulation material to either side of a pre-patterned thin foil conductor, and bonding the sides together via an adhesive to enclose the conductor therein. Current FFC terminals include piercing-style crimp terminals, wherein sharpened tines of a terminal are used to pierce the insulation and adhesive material of the FFC in order to attempt to establish a secure electrical connection with the embedded conductor. However, due in part to the fragile nature of the thin foil conductor material, these types of terminals have several drawbacks, including much higher electrical resistances compared to conventional round wire F-crimps, inconsistent electrical connectivity between the conductor and the terminal, and mechanical unreliability over time in harsh environments.
Accordingly, there is a need for improved electrical terminals and accompanying termination techniques for adapting FFCs to these environments.
SUMMARYAccording to an embodiment of the present disclosure, a terminal for mating with an exposed conductor of a flat flexible cable is provided. The terminal includes an electrical contact and a crimping portion extending from the electrical contact in a longitudinal direction of the terminal for crimping to the conductor of the flat flexible cable. The crimping portion comprises a base defining at least one protrusion extending therefrom, and first and second sidewalls extending from the base. The base and sidewalls define an opening configured to receive the conductor of the flat flexible cable therein. The sidewalls are foldable over one another and into the opening for crimping the conductor within the opening and generally between the protrusion of the base and a portion of the sidewalls.
A cable assembly according to an embodiment of the present disclosure includes a flat flexible cable having a plurality of conductors embedded within an insulation material. A portion of each of the conductors is exposed via windows or openings selectively formed in the insulation material, allowing for a crimping portion of an electrically conductive terminal to engage with the conductor within the opening. The crimping portion includes a base defining at least one protrusion extending therefrom, and first and second sidewalls extending from the base. The base and sidewalls define an opening configured to receive the exposed conductor therein, wherein the sidewalls are foldable into the opening for crimping the conductor within the opening and generally between the protrusion of the base and a portion of the sidewalls.
The invention will now be described by way of example with reference to the accompanying figures, of which:
Exemplary embodiments of the invention will be described hereinafter in detail with reference to the attached drawings, wherein like reference numerals refer to like elements. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art.
Reliably crimping a terminal onto a thin conductor of an FFC requires a means to address the risks of either failing to make suitable (or any) electrical contact with the conductor, or damaging the conductor via the application of excess pressure. This has proven difficult to achieve, in part due to the thin nature of the conductors of the FFC compared to the tolerances of typical crimp-style terminals. For example, with a thickness of less than a tenth of a millimeter (mm) (e.g., 0.07 mm), crimping height tolerances can easily exceed the thickness of the conductor, which may result in either a complete lack of electrical contact between the terminal and the conductor, or the crushing and destruction of the conductor, despite a proper crimping operation. As will be set forth in greater detail herein, embodiments of the present disclosure aim to address these difficulties, providing crimpable terminals that enable reliable, low-resistance connections to be realized in mass termination or crimping operations.
Terminals according to embodiments of the present disclosure may be configured for use with an FFC, such as the exemplary portion of an FFC 10 shown in
With reference to
As shown in
Referring to
As set forth above, reliably crimping to a thin conductor of an FFC requires a means to address the risks of either failing to make suitable electrical contact with the conductor, or damaging the conductor via the application of excess pressure. Embodiments of the present disclosure address this problem via the introduction of several additional features onto or into the base 44 of the crimping portion 40 to prevent either of the above failures.
Still referring to
Due in part to their curved nature, the compression limiters are configured (i.e., are sized and shaped) so as to compress a conductor under force from the crimped first and second sidewalls in a manner which will prevent damage thereto. Moreover, the added height of the compression limiters ensures that reliable electrical contact is always achieved with the conductor, addressing the above-described tolerance-related issues with crimping solutions of the prior art. Further, the height of the compression limiters may be selected so as to allow for crimp height and compressive force adjustments for a given application (e.g., for different thicknesses of conductors).
Still referring to
The apertures 74,76 formed through the first and second sidewalls 46,48 are positioned so as to correspond in location with the protruding sections 68 when the crimping portion 40 is in a crimped state, as shown in
Referring generally to
Referring to the embodiment of
Referring generally to
In the embodiment of a crimping portion 95 shown in
The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range. For example, it should also be understood that embodiments of the present disclosure may include any combination of the above-described features, such as various combinations of compression limiters and spring arrangements, and are not limited to the exemplary arrangements set forth in the figures.
Also, the indefinite articles “a” and “an” preceding an element or component of the invention are intended to be nonrestrictive regarding the number of instances, that is, occurrences of the element or component. Therefore “a” or “an” should be read to include one or at least one, and the singular word form of the element or component also includes the plural unless the number is obviously meant to be singular.
The term “invention” or “present invention” as used herein is a non-limiting term and is not intended to refer to any single embodiment of the particular invention but encompasses all possible embodiments as described in the application.
Claims
1. An electrical terminal for mating with an exposed conductor of a flat flexible cable, comprising:
- an electrical contact; and
- a conductive crimping portion extending from the electrical contact in a longitudinal direction of the terminal for crimping to the conductor of the flat flexible cable, the crimping portion including: a conductive base defining at least one protrusion extending therefrom; and first and second conductive sidewalls extending from the base, the base and sidewalls defining an opening extending in the longitudinal direction for receiving the conductor, each of the sidewalls being foldable relative to the base along a respective axis extending in the longitudinal direction and into the opening for crimping the conductor within the opening and generally between the protrusion of the base and at least a portion of the sidewalls.
2. The electrical terminal of claim 1, wherein the protrusion extends along the base in the longitudinal direction of the terminal.
3. The electrical terminal of claim 2, wherein the protrusion comprises a curved profile having an axis of curvature extending in the longitudinal direction of the terminal.
4. The electrical terminal of claim 3, wherein the protrusion comprises a first section extending into the opening a first distance, and a second section extending into the opening a second distance greater than the first distance.
5. The electrical terminal of claim 4, wherein at least one of the first or second sidewalls comprises an aperture formed therethrough in a direction transverse to the longitudinal direction, wherein in a crimped state of the crimping portion, the second section of the protrusion is configured to at least one of align or engage with the aperture.
6. The electrical terminal of claim 5, wherein the second section of the protrusion defines at least first and second edges extending in a direction transverse to the longitudinal direction of the terminal and configured to engage with the conductor arranged within the opening.
7. The electrical terminal of claim 3, wherein the protrusion comprises:
- first and second end protrusions;
- a central protrusion arranged between the first and second end protrusions;
- a first intermediate protrusion arranged between the first end protrusion and the central protrusion; and
- a second intermediate protrusion arranged between the second end protrusion and the central protrusion,
- wherein the first and second intermediate protrusions extend further into the opening than the first and second end protrusion and the central protrusion.
8. The electrical terminal of claim 7, wherein the first and second intermediate protrusions are configured to engage with a respective aperture formed in the first sidewall and second sidewall in a direction transverse to the longitudinal direction when the crimping portion of the terminal is in a crimped state.
9. The electrical terminal of claim 1, wherein the first sidewall comprises a first section and a second section, and the second sidewall comprises a first section and a second section opposing the first and second sections of the first sidewall, wherein a recess is formed through each of the first and second sidewalls between the first section and the second section.
10. The electrical terminal of claim 9, wherein in a crimped state, the first section of the second sidewall is folded over and overlaps the first section of the first sidewall, and the second section of the first sidewall is folded over and overlaps the second section of the second sidewall.
11. The electrical terminal of claim 10, wherein the first and second sections of each sidewall comprise different heights.
12. The electrical terminal of claim 11, wherein opposing first sections of the first and second sidewalls comprise different heights.
13. The electrical terminal of claim 10, wherein at least one of the first section of the first sidewall or the second section of the second sidewall comprises a serration on a side thereof facing the opening.
14. The electrical terminal of claim 13, wherein at least one of the first section of the first sidewall or the second section of the second sidewall comprises an aperture formed therethrough in an area of the serration and in a direction transverse to the longitudinal direction.
15. The electrical terminal of claim 14, wherein at least a portion of the protrusion is configured to at least one of align or engage with the aperture when the crimping portion is in a crimped state.
16. A cable assembly including:
- a flat flexible cable including a plurality of conductors embedded within an insulation material, wherein a portion of each of the conductors is exposed via openings selectively formed in the insulation material; and
- a plurality of electrically conductive terminals, each of the terminals having a conductive crimping portion at least partially engaging with the openings in the insulation material and receiving the exposed portion of a respective conductor, the crimping portion including: a conductive base defining at least one protrusion extending therefrom; and first and second conductive sidewalls extending from the base, the base and sidewalls defining an opening configured to receive the conductor therein, the sidewalls extending through one of the openings formed in the insulation material and being foldable into the opening for crimping the conductor within the opening and generally between the protrusion of the base and a portion of the sidewalls.
17. The cable assembly of claim 16, wherein the protrusion comprises a curved profile having an axis of curvature extending in a longitudinal direction of the terminal.
18. The cable assembly of claim 17, wherein the protrusion comprises a first section extending into the opening a first distance, and a second section extending into the opening a second distance greater than the first distance.
19. The cable assembly of claim 18, wherein at least one of the first or second sidewalls comprises an aperture formed therethrough, wherein in a crimped state of the crimping portion, the second section of the protrusion is configured to at least one of align or engage with the aperture.
20. The cable assembly of claim 17, wherein the protrusion comprises:
- first and second end protrusions;
- a central protrusion arranged between the first and second end protrusions;
- a first intermediate protrusion arranged between the first end protrusion and the central protrusion; and
- a second intermediate protrusion arranged between the second end protrusion and the central protrusion,
- wherein the first and second intermediate protrusions extend further into the opening than the first and second end protrusion and the central protrusion.
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Type: Grant
Filed: Jul 2, 2020
Date of Patent: Apr 5, 2022
Patent Publication Number: 20220006213
Assignee: TE Connectivity Services GmbH
Inventors: Hurley Chester Moll (Hershey, PA), John Mark Myer (Millersville, PA), Forrest Irving Kinsey, Jr. (Harrisburg, PA)
Primary Examiner: Jean F Duverne
Application Number: 16/919,926
International Classification: H01R 12/69 (20110101);